Thermal Analysis of a Jet Deflector Subjected to Liquid Engine Jet Exhaust in a Static Test

The survivability of a jet deflector encountering severe heating conditions due to the direct impingement of exhaust gases from a liquid engine is analyzed. Using engineering methods the thermal environments and temperature history are estimated. The cooling of the jet deflector using a water stream into the exhaust stream through spray nozzles located upstream from the deflector to reduce the exhaust temperature is considered. Since the major source of heating of the jet deflector is by convection, the convective heating due to jet impingement is evaluated. A flow field from the exhaust of the liquid engine is generated using a finite-volume-based Navier-Stokes computational fluid dynamics solver. For evaluating convective heat transfer coefficient, engineering methods are used based on the flow-field data generated. The theoretical flow-field data generated do not account for jet water mixing. To account for the water jet effect, an energy balance method is used to estimate the jet temperature and a one-dimensional thermal response analysis is carried out using in-house design code. The computed temperature data are compared with the measured temperature data and the survivability of the jet deflector is assured.